Numerous hinge assemblies are known in the prior art for thin sheet metal panels, such as those used to pivotally couple a door to a box containing electrical equipment. There are, however, numerous disadvantages to many of these prior art hinge assemblies. For example, many of them are not separable so that the door cannot readily be detached from the box. In addition, many of these prior art devices do not limit the pivotal movement of the door relative to the box so that such relative pivotal movement varies widely in an uncontrolled manner.
Moreover, many of these prior art hinge assemblies are very expensive to form, such as for example piano hinges. In addition, such hinges require considerable time to attach to the door and the box, especially since various parts must be carefully aligned along the pivotal axis. Finally, many of the prior art hinge assemblies have intricate curved or tubular portions which require complicated manufacture and exacting tolerances.
Examples of these prior art devices are disclosed in U.S. Pat. Nos. 610,010, issued on Aug. 30, 1898 to Winter; 974,953, issued on Nov. 8, 1910 to Darlinton; 2,570,992, issued on Oct. 9, 1951 to Thomas; 2,767,032, issued on Oct. 16, 1956 to Mitchell; 2,852,802, issued on Sept. 23, 1958 to Seby; 2,969,889, issued on Jan. 31, 1961 to Morterol; 3,348,259, issued on Oct. 24, 1967 to Wilhelmsen et al; and 3,878,585, issued on Apr. 22, 1975 to Morris.